Book/Report FZJ-2018-03233

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png
Diffusion von Helium in kubischraumzentrierten und hexagonalen Metallen



1990
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Jülich : Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag, Berichte des Forschungszentrums Jülich 2354, 95, 141 p. ()

Please use a persistent id in citations:

Report No.: Juel-2354

Abstract: Foil specimens (2.5 - 85.0 $\mu$m) of V, Fe (bcc) and Ti, Co and Mg (hcp) were homogenously implanted with helium to final concentrations between 0.001 ppm and 5 ppm. By subsequent thermal desorption measurements three regimes of different desorption behaviour were identified: 1) Free diffusion determined the helium-release as long as the mean distance between a helium atom and the surface was small compared to the mean distance between the helium atoms. For Titanium a substitutional mechanismen was proposed, while in all the other metals helium diffuses by a dissociative mechanism with recapture at thermal vacancies (Mg, Co) andimplantation-induced vacancies (V, Fe), respectively. 2) Free diffusion was reduced by the agglomeration of helium atoms. The amount of helium released during free diffusion depended on the thickness d and the helium-concentration co as 1 / d $\sqrt{C_{0}}$. This dependence was explained by a simple agglomeration-model.3) After the formation of helium-bubbles a small heliumrelease persisted. This could be explained by two different coarsening mechanismens: bubble-migration and -coalescence (e. g. Mg) and Ostwald-ripening (e. g. Ti).


Contributing Institute(s):
  1. Publikationen vor 2000 (PRE-2000)
Research Program(s):
  1. 899 - ohne Topic (POF3-899) (POF3-899)

Database coverage:
OpenAccess
Click to display QR Code for this record

The record appears in these collections:
Document types > Reports > Reports
Document types > Books > Books
Workflow collections > Public records
Institute Collections > Retrocat
Publications database
Open Access

 Record created 2018-05-29, last modified 2021-01-29